Zircon refractory compositions

ABSTRACT

A new refractory composition comprising from 70.0% to 96.8% zircon, from 3.0% to 29.8% iron-chromite ore and from 0.2% to 5.0% rutile titanium dioxide has been prepared which has a low porosity and high modulus of rupture.

United States Patent 1 1 Manigault Feb. 12, 1974 ZIRCON REFRACTORY COMPOSITTONS [56] References Cited [75] Inventor: Edward L. Manigault, Cincinnnati, UNITED STATES ATENTS O 3,181,958 5/1965 Thomas 106/57 [73] Assignee: The Chas. Taylor & Sons Company,

Cincinnati, Ohio Primary ExammerJames E. Poer [22] Filed: May 31, 1972 57] T T [21] Appl. No.: 258,459 A new refractory composition comprising from 70.0% to 96.8% zircon, from 3.0% to 29.8% iron-chromite ore and from 0.2% to 5.0% rutile titanium dioxide has Fur-5:85 :11:r:-::-.:;:.:v

- been prepared which has a low porosity and high mod- [58] Field of Search 10651613, rupture- 4 Claims, No Drawings 1 ztRcoN REFRACTORY coMrosmons BACKGROUND OF THE INVENTION Many types of ceramic compositions have been prepared in the past which have given good service in glass contact and back-up linings for the glass industry. One particular type of ceramic composition which is particularly useful is the so-called zircon brick which may consist of from 96% to 99% zirconium silicate, and from 1% to 4% other oxides. Although these zircon bricks are commercially useful, it has been found that the composition may be modified to produce a superior type of brick which has an increased modulus of rupture, an increased bulk density and a decreased porosity. In addition, the brick is more resistant to penetration by metal and metallic oxide often present when tramp metal is unintentionally introduced in the glass batch with recycled glass. This new refractory is particularly useful as a back-up, or sub-floor, under the glass contact bottom blocks in a glassmelting tank.

SUMMARY OF THE INVENTION A new ceramic composition has been produced comprising from 70.0% to 96.8% zircon, from 3.0% to DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been found the iron-chromite ore may be added as a modifying agent and that not only are superior results obtained but that the addition of ironchromite ore reduces the cost of the product since ironchromite ore is less expensive than zircon itself.

Iron-chromite ore usually contains from 35% to 50% chromic oxide, from to 35% iron oxides and from 20% to 45% oxides of silicon, magnesium, calcium and aluminum.

In preparing the new refractory composition of the instant invention, the zircon (zirconium silicate) is milled to -70 mesh. The iron-chromite ore and the rutile are ground to 325 mesh size.

The three ingredients are thoroughly mixed with water and lignin liquor to temper the mixture and the mixture is then pressed into shapes and fired at a temperature between l,450 and 1,600 C.

When the instant refractory product is compared with the zircon prior art products, it has been found that the general physical properties of the instant product are improved. The bulk density and the modulus of rupture are both increased while the porosity is decreased. The instant refractory product is also more resistant to iron oxide penetration than the prior art product.

In order to describe more fully the instant invention, the following examples are presented:

EXAMPLE 1 The iron-chromite ore used in this Example had the following typical analysis:

Ingredient Percentage Chromic Oxide 45.66!- lron Oxides 27.24% Alumina 15.26% Silica 1.47% Magnesium Oxide 10.24%- Calcium Oxide 0.13%

90 kg of zircon mesh) were mixed with 10 kg of iron-chromite ore and 0.4 kg of rutile. Both the ironchromite ore and the rutile were -325 mesh size.

3 kg of an organic binder and 1.1 kg of water were mixed with the above ingredients to .temper the mixture. The mixture was then formed into bricks 9" X 4% X 3 and were fired at 1560 C for 5 hours.

The fired bricks had the following properties:

Modulus of Rupture, psi 4061 Porosity, 15.0 Bulk Density, g/cc 3.89

Bulk Density, g/cc etration was 2% inches. A

These properties are superior to a typical standard zircon brick which possesses the following properties:

Modulus of Rupture, psi Porosity,

In order to show the bricks resistance toward penetration of tramp metal into the brick, the following test was run:

A 54 inch black steel nut was placed on the surface .of the brick produced and the brick was heated to 2 2,850 F for 5 hours. After cooling the depth of penetration of the iron oxide into the brick was measured as inch.

For comparison a prior art zircon brick was subjected to the same test and it was found that the depth of pen- EXAMPLES 2-4 In these examples the procedure of Example 1 was repeated except that varying amounts of the ingredients were employed. The amounts of ingredients used and the results obtained are recorded in the table along with those of Example 1 and the prior art zircon" bricks.

From the table it has clearly been shown that the bricks formed using the ingredients described in the instant invention produce over-all superior results to those obtained by the prior art zircon bricks. The products possessed superior modulus of rupture, increased bulk density, decreased porosity and greater resistance toward iron penetration than the zircon bricks of the prior art.

While this invention has been described and illustrated by the examples shown, it is not intended to be strictly limited thereto, and other variations and modifications may be employed within the scope of the following claims.

TABLE 1 EXAMPLE NO.

INGREDIENTS 1 l 2 3 4 PRIOR-ART ZIRCON BRICK Zircon, kg 90 97 80 70.2 99 iron-Chromite, kg 3 29.8 Rutile, kg 0.4 0.4 0.4 0.3 1.0 PROPERTIES Modulus of Rupture, psi 4016 3982 3462 2703 2300 Porosity, 15.0 17.6 16.9 13.6 17.5 Bulk Density, g/cc 1 3.89 3.78 3.77 3.88 3.72 Nut Test, Depth of in. 2% in.

Penetration, inches chromite ore and rutile titanium dioxide, the amount of 5 said zircon in said mixture being from 70% to 96.8%,

v the amount of iron-chromite ore being from 3.0% to 29.8%, and the amount of rutile titanium dioxide being from 0.2% to 5.0%, all percentages expressed by weight, forming the mixture into a ceramic shaped body, and firing the shaped body at a temperature from 1,450" C to 1,600 C to produce said refractory composition.

3. Method according to claim 2 in which the ironchromite ore contained from 35% to 50% chromicoxide, from 20% to 35% iron oxides and from 20% to 45% oxides of silicon, magnesium, calcium and aluminum.

4. Method according to claim 2 in which said zircon is of size mesh, said iron-chromite ore and said rutile titanium dioxide are -325 mesh in size.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 7 834 Datea February 12, 1974 Inventor(S) EDWARD L. MANIGAULT It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Assignee: THE CHAS. TAYLOR'S SONS COMPANY Signed and sealed this 16th day of July 197A.

(SEAL) Attest:

McCOY 1 1. GIBSON, JR. C. MARSHALL DANN Attestinp; Officer Commissioner of Patents USCOMM-DC 60376-P69 FQRM POJOSO (10-69) r us. GOVERNMENT rnnmue orrlcg lacs o-aes-au 

2. A method for preparing a refractory composition having a high modulus of rupture and low porosity which comprises thoroughly mixing zircon, an iron-chromite ore and rutile titanium dioxide, the amount of said zircon in said mixture being from 70% to 96.8%, the amount of iron-chromite ore being from 3.0% to 29.8%, and the amount of rutile titanium dioxide being from 0.2% to 5.0%, all percentages expressed by weight, forming the mixture into a ceramic shaped body, and firing the shaped body at a temperature from 1,450* C to 1,600* C to produce said refractory composition.
 3. Method according to claim 2 in which the iron-chromite ore contained from 35% to 50% chromic-oxide, from 20% to 35% iron oxides and from 20% to 45% oxides of silicon, magnesium, calcium and aluminum.
 4. Method according to claim 2 in which said zircon is of size -70 mesh, said iron-chromite ore and said rutile titanium dioxide are -325 mesh in size. 